1. Field of the Invention
The present invention relates to an image forming system.
2. Description of Related Art
Lately, there is known an image forming system in which a plurality of image forming apparatuses such as printers, copiers, etc. which form an image on paper are provided in a series and each image forming apparatus forms an image on one face of the paper to realize double face printing so that the productivity is enhanced.
Regarding such image forming system, Japanese Patent Application Laid-Open Publication No. 7-237336 describes a technique in which an intermediate buffer apparatus is provided between two printers, paper on which an image is formed on a front face by a first printer is sent to the intermediate buffer apparatus, and the paper is received by a second printer from the intermediate buffer apparatus and an image is formed on a back face by the second printer. In such image forming system, suitable double face printing is realized by stopping printing and paper feeding by the first printer or the second printer according to accumulated amount of paper in the intermediate buffer apparatus.
Since the content of image forming processing in each of the plurality of image forming apparatuses in such image forming system is different, suitable timing to perform adjustment for suitable image forming is different for each image forming apparatus. Therefore, when adjustment of one image forming apparatus starts during image forming processing of the other image forming apparatus, the other image forming apparatus needs to standby until the adjustment in the one image forming apparatus is complete.
However, in an image forming system as described in the above Japanese Patent Application Laid-Open Publication No. 7-237336, due to property of the configuration, it is necessary to monitor not only the accumulating amount of continuous paper in the intermediate buffer apparatus becoming large but also the amount becoming small, and based on the above, the control of driving the apparatuses in each of the two printers is performed. However, in an image forming system which includes a plurality of image forming apparatuses which perform image forming on each paper of a certain size instead of continuous paper, it is normal that the paper does not accumulate, and therefore such monitoring is not necessary.
In such image forming system, for example, when adjustment of an image forming apparatus in an upstream side is performed for a long period of time, an image forming apparatus in a downstream side cannot recognize this. Therefore, various apparatuses for performing image forming processing are on standby while being driven (idle running). Consequently, problems occur in the image forming apparatus such as deterioration of material and waste of energy of the apparatus, and therefore it is inefficient.